A significant number of phone sets in use and in production are wireline stimulus phones, where the control of call processing and device display reside on the switches and not on the phones. In this environment, it is very difficult for application developers to develop features that can control the display on stimulus phone sets. Generally, the developers must possess the knowledge and have access to the switches to embed their applications. This is time-consuming and it is not conducive to fast development and deployment of applications. It is also difficult or impossible for developers to reuse their code across multiple platforms.
This situation is also problematic for switch vendors. Multiple services are desirable for deployment on PBX systems to satisfy customer needs. However, if the developers are required to have knowledge of and access to the switches, then it is unlikely that multiple applications can be deployed quickly or cost effectively.
Furthermore, stimulus phone set users are generally only provided with a fixed set of features to personalize their phone sets. There is a lack of applications available for such users. It would be advantageous to provide users with the ability to customize their phone sets for the applications that they find useful in addition to call control and messaging services. The applications most readily available are the vast and rapidly increasing number of services available on intranets and the Internet. Currently, web access is not available using a stimulus phone set.
An approach to providing web access is to incorporate browsers in the phone sets and wireless devices. This is exemplified by the development of Wireless Application Protocol (WAP) for wireless devices. However, PBX networks do not have the same security and bandwidth limitations as wireless networks, it is inefficient and unnecessary to have wireless transport or encryption layers of WAP taking up valuable resources on stimulus phone sets. Further, a stripped WAP browser may still have problems on stimulus phone sets which have very limited resources.
A further problem with putting browsers on stimulus phone sets is that the call processing and display functions reside on the switches. Browsers require these control features to operate properly. It is very difficult for browsers to access these control features from the phone sets. To enable installation of a browser, major changes are required to the switch-device relationship between the stimulus phone sets and their switches.
It is therefore desirable to provide browser functions to stimulus phone sets, which address the shortcomings of providing browser functions as noted above.